The present invention relates to seal arrangements and particularly but not exclusively, to seal arrangements for use in liquid concentrators.
A liquid concentrator is an apparatus in which an evaporation process can result in a more concentrated liquid. In an agricultural based economy such as New Zealand, such apparatus has particular application in the concentration of milk.
The benefits to be derived from milk volume reduction are numerous and of tremendous commercial importance. It will be appreciated that by removing a substantial amount of the water contained in the milk in its natural state, the cost of collection, transporting and processing the milk can be substantially reduced.
In apparatus such as concentrators, various rotary and/or static seals are required to ensure that the prescribed pressures and/or vacuums are maintained and that there is no cross contamination of the fluid flows across the various parts of the apparatus.
In developing its concentrator technology, the applicant has developed the present invention for use in apparatus such as concentrators. To the present time, various sealing arrangements have been proposed to particular type of apparatus. In U.S. Pat. No. 4,902,197 (Rhodes et al), a seal arrangement for a centrifugal type of pump prevents fluid such as steam, pressurised by the pump, from escaping from the pump housing. The sealing arrangement consists of a continuous liquid seal extending circumferentially around an axial section of the shaft assembly of the pump, the liquid being held in place by the centrifugal action of the pump rotor and by the positive pressure gradient existing between the interior of the pump housing and its exterior.
While the present invention will be described hereinafter in its various embodiments with particular reference to a liquid concentrator, it will be appreciated by those skilled in the engineering arts that the sealing arrangements of the present invention may find application wherever an appropriate seal is required to be provided.